Integrating a communication bridge into a data processing system

ABSTRACT

Integrating a further communication bridge into a running data processing system. The data processing system includes a communication client running a first operating system having no own communication stack and at least a first communication bridge running a second operating system having an own communication stack. The first communication bridge is configured as a master communication bridge. The further communication bridge announces itself as a slave communication bridge at an announcement time. The master communication bridge executes a quiesce process on the network adapter and on the API of the communication client when there are no data packets in the queue with a sending time earlier than the announcement time. The master communication bridge extracts the state of its communication stack and sends it to the further communication bridge. The master communication bridge resumes the network adapter and the API.

BACKGROUND

One or more aspects of the present invention relate in general to dataprocessing systems, and in particular, to integrating a communicationbridge into a data processing system and external networks.

A device for processing network communication that increases the speedof that processing and the efficiency of transferring data beingcommunicated has been described. The protocol processing method andarchitecture effectively collapses the layers of a connection-based,layered architecture such as TCP/IP, into a single wider layer which isable to send network data more directly to and from a desired locationor buffer on a host. This accelerated processing is provided to a hostfor both transmitting and receiving data, and so improves performancewhether one or both hosts involved in an exchange of information havesuch a feature. The accelerated processing includes employingrepresentative control instructions for a given message that allow datafrom the message to be processed via a fast-path which accesses messagedata directly at its source or delivers it directly to its intendeddestination. This fast-path bypasses conventional protocol processing ofheaders that accompany the data. The fast-path employs a specializedmicroprocessor designed for processing network communication, avoidingthe delays and pitfalls of conventional software layer processing, suchas repeated copying and interrupts to the CPU. In effect, the fast-pathreplaces the states that are traditionally found in several layers of aconventional network stack with a single state machine encompassing allthose layers, in contrast to conventional rules that require rigorousdifferentiation and separation of protocol layers. The host retains asequential protocol processing stack which can be employed for settingup a fast-path connection or processing message exceptions. Thespecialized microprocessor and the host intelligently choose whether agiven message or portion of a message is processed by the microprocessoror the host stack.

Also, previously described is a method of generating a fast-pathresponse to a packet received onto a network interface device where thepacket is received over a TCP/IP network connection and where the TCP/IPnetwork connection is identified at least in part by a TCP source port,a TCP destination port, an IP source address, and an IP destinationaddress. The method includes: 1) Examining the packet and determiningfrom the packet the TCP source port, the TCP destination port, the IPsource address, and the IP destination address; 2) Accessing anappropriate template header stored on the network interface device. Thetemplate header has TCP fields and IP fields; 3) Employing a finitestate machine that implements both TCP protocol processing and IPprotocol processing to fill in the TCP fields and IP fields of thetemplate header; and 4) Transmitting the fast-path response from thenetwork interface device. The fast-path response includes the filled intemplate header and a payload. The finite state machine does not entaila TCP protocol processing layer and a discrete IP protocol processinglayer where the TCP and IP layers are executed one after another insequence. Rather, the finite state machine covers both TCP and IPprotocol processing layers. Buffer descriptors that point to packets tobe transmitted are pushed onto a plurality of transmit queues. Atransmit sequencer pops the transmit queues and obtains the bufferdescriptors. The buffer descriptors are then used to retrieve thepackets from buffers where the packets are stored. The retrieved packetsare then transmitted from the network interface device. There are twotransmit queues, one having a higher transmission priority than theother. Packets identified by buffer descriptors on the higher prioritytransmit queue are transmitted from the network interface device beforepackets identified by the lower priority transmit queue.

SUMMARY

In accordance with one or more aspects, a new or recovered communicationbridge is integrated into a running data processing system and externalnetworks with increased reliability.

According to one aspect, a method of integrating a further communicationbridge into a running data processing system is provided. The methodincludes obtaining, by a master communication bridge of the dataprocessing system, an announcement made at an announcement time by thefurther communication bridge of the data processing system announcingthat the further communication bridge is a slave communication bridge,the further communication bridge being a new or a recoveredcommunication bridge. The data processing system includes acommunication client running a first operating system having no owncommunication stack, and a first communication bridge running a secondoperating system having an own communication stack, wherein the firstcommunication bridge is configured to act as the master communicationbridge and wherein the further communication bridge is running a thirdoperating system having an own communication stack. Master and slave aredesignations that are switched from one communication bridge to anothercommunication bridge based on an event. The first communication bridgeand the further communication bridge communicate by exchanging systemstate information on a regular basis. The master communication bridgemonitors data packets in a queue of its communication stack. The mastercommunication bridge executes a quiesce process to quiesce processing ona network adapter and on an application programming interface (API) ofthe communication client based on there being no data packets in thequeue with a sending time earlier than the announcement time. The mastercommunication bridge extracts state of its communication stack and sendsit to the further communication bridge. The master communication bridgeobtains an indication of completion by the further communication bridgeof setting the received state in its own communication stack. The mastercommunication bridge resumes the network adapter and the API, whereinthe master communication bridge and the further communication bridge arein synchronization.

Computer program products and systems related to one or more aspects arealso described and may be claimed herein.

BRIEF DESCRIPTION OF THE DRAWINGS

Aspects of the present invention together with the other objects andadvantages may best be understood from the following detaileddescription of the embodiments, but not restricted to the embodiments,wherein is shown in:

FIG. 1 a data flow of inbound communication traffic in a data processingsystem according to an embodiment of the invention using TCP/IPcommunication stacks and an OSA card for communicating with a network;

FIG. 2 a flowchart for executing inbound communication traffic in a dataprocessing system according to an embodiment of the invention;

FIG. 3 a flowchart for executing one or more aspects for integrating anew or recovered communication bridge in a running data processingsystem according to an embodiment of the invention; and

FIG. 4 an example embodiment of a data processing system for executing amethod according one or more aspects of the invention.

DETAILED DESCRIPTION

In the drawings, like elements are referred to with equal referencenumerals. The drawings are merely schematic representations, notintended to portray specific parameters of aspects of the invention.Moreover, the drawings are intended to depict only typical embodimentsof the invention, and therefore, should not be considered as limitingthe scope of aspects of the invention.

FIG. 1 shows a data flow of inbound communication traffic in a dataprocessing system 210 according to an embodiment of the invention usingTCP/IP communication stacks 20, 22 and an OSA card as a network adapter68 for communicating with a network 30. The network 30 is sendingincoming data through the communication stacks 20, 22 to both the atleast first and the further communication bridges 12, 14, where thecurrent master communication bridge 26 is sending the incoming data tothe communication client 10.

The first communication bridge 12 and the further communication bridge14 communicate by exchanging system state information 36 on a regularbasis, the system state information 36 comprising information about astatus of the outgoing data and the incoming data.

The communication client 10, and/or the first communication bridge 12,and/or the further communication bridge 14 are implemented as virtualmachines in the data processing system 210.

Communication between the communication client 10 and/or thecommunication bridges 12, 14 is performed by daemons 64, 66 running onthe communication bridges 12, 14, wherein communication between thecommunication client 10 and/or the communication bridges 12, 14 isperformed via a communication mechanism 24. The communication mechanism24 is implemented, for instance, as a socket network. Alternatively, thecommunication mechanism 24 could also be implemented as a remote directmemory access network. The own communication stacks 20, 22 of thecommunication bridges 12, 14 are TCP stacks. The system stateinformation 36 comprises heartbeat information. The system stateinformation 36 contains information about a data packet count sentand/or received by the master communication bridge 26. The system stateinformation 36 also contains information about an identifier for thelast data packet sent and/or received.

The first operating system 16 and/or the second operating system 18and/or the third operating system 19 can be a Linux operating system.Alternatively, other conventional operating systems may be used.

Data packets are sent from the network 30 via connection 54 to the OSAcard 68 and from there via connections 50 and 52 to the TCP/IPcommunication stacks 20, 22 of the communication bridges 12, 14. Themaster communication bridge 26 is sending the data packets through thedaemon 64 and the communication mechanism 24, implemented as a socketnetwork, via connection 42 to the API 62 of the communication client 10,so that the data packets may be received by the program 60 running onthe communication client 10. Via the system state information 36 as aheartbeat it is checked if the master communication bridge 26 is stillalive and functional. The connection 44 is marked with a dash-dottedline, because the slave communication bridge 28 is not sending any data,as long as the master communication bridge 26 is still alive. Otherwise,the former slave communication bridge 28 would be switched to the newmaster communication bridge and the data packets would be sent by thenew master communication bridge 14 to the communication client 10.

FIG. 2 shows one example of a flowchart for executing inboundcommunication traffic in a data processing system 210 according to anembodiment of the invention, as depicted in FIG. 1. The OSA card 68receives a data packet in step S200 from a client/network 30 andforwards it in step S202 to both communication bridges 12, 14. In stepS204 in both communication bridges 12, 14 the TCP/IP communicationstacks 20, 22 process the data packet and forward it to the daemons 64,66. The master daemon 64 on the master communication bridge 26 adds aheader (including its internal incoming packet counter) to the datapacket, step S206, and forwards the data packet (including the header)in step S208 via the socket network as a communication mechanism 24 tothe API 62 on the communication client 10. The slave daemon 66 buffersthe data packet. Both daemons 64, 66 increase their internal incomingpacket counter. There are multiple options/alternatives of the usage ofthe packet counter. One packet counter may be used for each connection.Alternatively, one packet counter may be used for all connections. It isfavorable for failover scenarios that the same data packets get the sameinternal packet counter, so that in a failover the slave communicationbridge 28 can resend the correct data packets. It is also an option touse an internal packet counter based on the protocol. So, e.g., thesequence number of TCP packets may be reused. Or for user datagramprotocol (UDP), no counter may be used, because this protocol isstateless and data packets may always be dropped. The API 62 receivesthe data packet in step S210 and reads the header, step S212. If theinternal incoming packet counter is less than or equal to the internalincoming packet counter of the last received data packet, it drops thedata packet (cleanup of data packets processed). The API 62 forwards thedata packet to the corresponding application/program 60 in step S214.

FIG. 3 is illustrating one example of an execution of one or moreaspects of the method for integrating a further communication bridge 14in a running data processing system 210 according to an embodiment ofthe invention. The further communication bridge 14 is a new or recoveredcommunication bridge 14. There may be several other communicationbridges present. The method allows to integrate the furthercommunication bridge 14 into the data processing system 210, where thedata processing system 210 is comprising a communication client 10running a first operating system 16 having no own communication stackand a first communication bridge 12 running a second operating system 18having an own communication stack 20, wherein the first communicationbridge 12 is being configured to act as a master communication bridge 26and wherein the further communication bridge 14 is running a thirdoperating system 19 having an own communication stack 22.

The flow in FIG. 3 according one or more aspects begins by starting thefurther communication bridge 14 in step S300. Next in step S302, thefurther communication bridge 14 is requesting from a network adapter 68and an API 62 of the communication client 10 to receive data packetsthey are communicating. If this is fulfilled, in step S304 the furthercommunication bridge 14 is buffering the data packets it receives. Then,in step S306, the further communication bridge 14 is announcing itselfas a slave communication bridge 28 to the master communication bridge 26at an announcement time via a communication mechanism 24, by e.g., aheartbeat 36. When the master communication bridge 26 receives theannouncement of the new slave communication bridge 28, then in stepS308, the master communication bridge 26 is monitoring the data packetsin a queue of its communication stack 20, followed by the mastercommunication bridge 26 executing a quiesce process on the networkadapter 68 and on the API 62 of the communication client 10 in stepS310, when there are no data packets in the queue with a sending timeearlier than the announcement time. Further the master communicationbridge 26 is extracting in step S312 the state of its communicationstack 20 and sending it to the further communication bridge 14 as aslave communication bridge 28. In step S314 the further communicationbridge 14 is setting the received state in its own communication stack22 and informing the master communication bridge 26 about completion ofthe step. Finally, in step S316, the master communication bridge 26 isresuming the network adapter 68 and the API 62. Thus, at the end of theflow, the master communication bridge 26 and the new or recoveredfurther communication bridge 14 as a slave communication bridge 28 arein synchronization.

Referring now to FIG. 4, a schematic of an example of a data processingsystem 210 is shown. Data processing system 210 is only one example of asuitable data processing system and is not intended to suggest anylimitation as to the scope of use or functionality of embodiments of theinvention described herein. Regardless, data processing system 210 iscapable of being implemented and/or performing any of the functionalityset forth herein above.

The data processing system 210 is capable of running a computer programproduct comprising a computer usable medium including a computerreadable program, wherein the computer readable program when executed ona computer system 212 causes the computer system 212 to perform a methodfor integrating a further communication bridge 14, being a new orrecovered communication bridge 14, into the running data processingsystem 210, where the data processing system 210 is comprising acommunication client 10 running a first operating system 16 having noown communication stack and a first communication bridge 12 running asecond operating system 18 having an own communication stack 20, whereinthe first communication bridge 12 is being configured to act as a mastercommunication bridge 26 and wherein the further communication bridge 14is running a third operating system 19 having an own communication stack22. The method includes starting the further communication bridge 14;the further communication bridge 14 requesting from a network adapter 68and an API 62 of the communication client 10 to receive data packets;and, the further communication bridge 14 buffering the data packets.Further, the method includes the further communication bridge 14announcing itself as a slave communication bridge 28 to the mastercommunication bridge 26 at an announcement time; the mastercommunication bridge 26 monitoring the data packets in a queue of itscommunication stack 20; and the master communication bridge 26 executinga quiesce process on the network adapter 68 and on the API 62 of thecommunication client 10 when there are no data packets in the queue witha sending time earlier than the announcement time. Further, the methodincludes the master communication bridge 26 extracting the state of itscommunication stack 20 and sending it to the further communicationbridge 14; the further communication bridge 14 setting the receivedstate in its own communication stack 22 and informing the mastercommunication bridge 26 about completion; and finally, the mastercommunication bridge 26 resuming the network adapter 68 and the API 62.

In data processing system 210, there is a computer system/server 212,which is operational with numerous other general purpose or specialpurpose computing system environments or configurations. Examples ofwell-known computing systems, environments, and/or configurations thatmay be suitable for use with computer system/server 212 include, but arenot limited to, micro-controllers, personal computer systems, servercomputer systems, thin clients, thick clients, handheld or laptopdevices, multiprocessor systems, microprocessor-based systems, set topboxes, programmable consumer electronics, network PCs, minicomputersystems, mainframe computer systems, and distributed cloud computingenvironments that include any of the above systems or devices, and thelike.

Computer system/server 212 may be described in the general context ofcomputer system executable instructions, such as program modules, beingexecuted by a computer system. Generally, program modules may includeroutines, programs, objects, components, logic, data structures, and soon that perform particular tasks or implement particular abstract datatypes. Computer system/server 212 may be practiced in distributed cloudcomputing environments where tasks are performed by remote processingdevices that are linked through a communications network. In adistributed cloud computing environment, program modules may be locatedin both local and remote computer system storage media including memorystorage devices.

As shown in FIG. 4, computer system/server 212 in data processing system210 is shown in the form of a general-purpose computing device. Thecomponents of computer system/server 212 may include, but are notlimited to, one or more processors or processing units 216, a systemmemory 228, and a bus 218 that couples various system componentsincluding system memory 228 to processor 216. Bus 218 represents one ormore of any of several types of bus structures, including a memory busor memory controller, a peripheral bus, an accelerated graphics port,and a processor or local bus using any of a variety of busarchitectures. By way of example, and not limitation, such architecturesinclude Industry Standard Architecture (ISA) bus, Micro ChannelArchitecture (MCA) bus, Enhanced ISA (EISA) bus, Video ElectronicsStandards Association (VESA) local bus, and Peripheral ComponentInterconnect (PCI) bus.

Computer system/server 212 typically includes a variety of computersystem readable media. Such media may be any available media that isaccessible by computer system/server 212, and it includes both volatileand non-volatile media, removable and non-removable media.

System memory 228 can include computer system readable media in the formof volatile memory, such as random access memory (RAM) 230 and/or cachememory 232. Computer system/server 212 may further include otherremovable/non-removable, volatile/non-volatile computer system storagemedia. By way of example only, storage system 234 can be provided forreading from and writing to a non-removable, non-volatile magnetic media(not shown and typically called a “hard drive”). Although not shown, amagnetic disk drive for reading from and writing to a removable,non-volatile magnetic disk (e.g., a “floppy disk”), and an optical diskdrive for reading from or writing to a removable, non-volatile opticaldisk such as a CD-ROM, DVD-ROM or other optical media can be provided.In such instances, each can be connected to bus 218 by one or more datamedia interfaces. As will be further depicted and described below,memory 228 may include at least one program product having a set (e.g.,at least one) of program modules that are configured to carry out thefunctions of embodiments of the invention.

Program/utility 240, having a set (at least one) of program modules 242,may be stored in memory 228 by way of example, and not limitation, aswell as an operating system, one or more application programs, otherprogram modules, and program data.

Each of the operating system, one or more application programs, otherprogram modules, and program data or some combination thereof, mayinclude an implementation of a networking environment. Program modules242 generally carry out the functions and/or methodologies ofembodiments of the invention as described herein.

Computer system/server 212 may also communicate with one or moreexternal devices 214 such as a keyboard, a pointing device, a display224, etc.; one or more devices that enable a user to interact withcomputer system/server 212; and/or any devices (e.g., network card,modem, etc.) that enable computer system/server 212 to communicate withone or more other computing devices. Such communication can occur viaInput/Output (I/O) interfaces 222. Still yet, computer system/server 212can communicate with one or more networks such as a local area network(LAN), a general wide area network (WAN), and/or a public network (e.g.,the Internet) via network adapter 220. As depicted, network adapter 220communicates with the other components of computer system/server 212 viabus 218. It should be understood that although not shown, other hardwareand/or software components could be used in conjunction with computersystem/server 212. Examples, include, but are not limited to: microcode,device drivers, redundant processing units, external disk drive arrays,RAID systems, tape drives, and data archival storage systems, etc.

As described herein, according to one aspect of the invention, a methodis provided for integrating a further communication bridge, being a newor recovered communication bridge, into a running data processingsystem, the data processing system comprising a communication clientrunning a first operating system having no own communication stack andat least a first communication bridge running a second operating systemhaving an own communication stack, wherein the first communicationbridge being configured to act as a master communication bridge andwherein the further communication bridge is running a third operatingsystem having an own communication stack. The method includes startingthe further communication bridge; the further communication bridgerequesting from a network adapter and an API of the communication clientto receive data packets; the further communication bridge buffering thedata packets. The method further includes the further communicationbridge announcing itself as a slave communication bridge to the mastercommunication bridge at an announcement time; the master communicationbridge monitoring the data packets in a queue of its communicationstack; the master communication bridge executing a quiesce process onthe network adapter and on the API of the communication client whenthere are no data packets in the queue with a sending time earlier thanthe announcement time. Further, the method includes the mastercommunication bridge extracting the state of its communication stack andsending it to the further communication bridge; the furthercommunication bridge setting the received state in its own communicationstack and informing the master communication bridge about completion;and the master communication bridge resuming the network adapter and theAPI.

A communication bridge is defined as a computing platform beingimplemented as a virtual or physical machine and running an ownoperating system, which may be Linux or any other commercial orproprietary operating system. The third operating system of the furthercommunication bridge may be the same kind of operating system as thesecond operating system of the first communication bridge.Alternatively, the operating systems may be different kinds of operatingsystems.

A communication client is defined as a computing platform beingimplemented as a virtual or physical machine and running an ownoperating system, which may be any commercial or proprietary operatingsystem. The communication client utilizes one or more services from acommunication bridge. The communication client may be implemented as aserver, but is called a client because it uses services from thecommunication bridges as a client.

Selected communication stack (e.g. TCP/IP, or other protocol stack)applications running on the communication client can communicate with acommunication stack of a communication bridge without using acommunication stack on the communication client. All socket requests,for example, may be transparently forwarded to the communication bridge,operating on the same virtual machine, or as another virtual machine onthe same data processing system, or operating on a different dataprocessing system.

Thus, it is not necessary to develop communication stacks, such as aTCP/IP stack, for all available computing platforms, but instead it ispossible to utilize already developed communication stacks on certaincomputing platforms, which may be accessed by employing one or moreaspects of the method of communicating between a communication clientand communication bridges.

Further, it is not necessary to develop code/support for a new hardware,such as a new network card, for all available computing platforms, butinstead, it is possible to utilize already developed communicationstacks on certain computing platforms, which may be accessed byemploying one or more aspects of the method of communicating between acommunication client and communication bridges.

The reliability of routing communication in a computing environment isincreased by using, e.g., more than one communication bridge on a dataprocessing system. The communication bridges are extended to exchangesystem state information, like a heartbeat, with the other communicationbridges and do a failover if necessary, i.e. change a former slavecommunication bridge to a new master communication bridge, if the formermaster communication bridge fails.

A heartbeat can generally be understood as a periodic signal generatedby hardware or software to indicate normal operation or to synchronizeother parts of the data processing system. Usually, a heartbeat is sentbetween communication bridges at a regular interval of the order ofmilliseconds. If a heartbeat isn't received for a time usually a fewheartbeat intervals—the communication bridge that should have sent theheartbeat is assumed to have failed.

One or more aspects aim at adding recoverability to a redundant dataprocessing system, as for example, a Linux fast-path environment. In oneexample, a method is described for integrating a new or recoveredcommunication bridge into existing network connections withoutdisruption of the running data processing system. This is enabled byextending a communication stack with an application programminginterface (API) in order to be able to read/set the TCP stack state,concerning a data packet counter for connections and the like. The dataprocessing system where the new or recovered communication bridge isintegrated in, may be running already at least one first communicationbridge, so that the new or recovered communication bridge would be thesecond communication bridge in the data processing system. Yet therecould also be already more than one communication bridge running in thedata processing system, so that the new or recovered communicationbridge would only be one additional communication bridge running in thedata processing system.

One or more aspects enable a hot plug of a new communication bridge orrecovering of a temporary failure of a communication bridge. In bothscenarios according to one or more aspects, the new or recoveredcommunication bridge will be integrated in a current high availabilitysetup of a data processing system. Thus, it is also possible tointegrate existing connections into a new communication bridge which isof considerable advantage for maintenance situations, where no coldstart needs to be carried out. Further, a recovery of the redundancy ofa data processing system, and an increase in capacity of the dataprocessing system are provided. One or more aspects may pertain to longlasting connections over hours or even days.

According to one or more aspects, a new or recovered communicationbridge will be started on the data processing system. Then, the new orrecovered communication bridge requests from a network adapter, like anOSA card and an API of a communication client, to get all data packetsthey are transferring. If a daemon running on the new or recoveredcommunication bridge gets the data packets, the daemon buffers the datapackets. Then the daemon announces itself as a new slave daemon to adaemon running on the master communication bridge being executed on thedata processing system, e.g. via a heartbeat connection. When the masterdaemon receives the announcement of the new slave daemon, it monitorsthe data packets in the queue of its communication stack. When there areno older data packets than the point in time when it received theannouncement, then it executes a quiesce process on the network adapterfor this communication bridge and on the API of the communicationclient. The master daemon extracts the state of the communication stackand sends it to the slave daemon. The slave daemon sets the state itreceived in its own communication stack and informs the master daemonabout completion. After that the master daemon resumes the networkadapter and the API. Now the master daemon and the slave daemon, andthus the communication bridges they are running, are synchronized.

In one embodiment, the first communication bridge and the furthercommunication bridge communicate by exchanging system state informationon a regular basis, the system state information comprising informationabout a status of the outgoing data and the incoming data.

The communication client, and/or the first communication bridge, and/orthe further communication bridge are implemented, e.g., as virtualmachines in the data processing system.

Virtual machines or logical partitions are commonly used in dataprocessing systems, and thus, may be used as a computing platformimplementing one or more aspects of the method.

Due to one embodiment, communication between the communication clientand/or the communication bridges may be performed by daemons running onthe communication bridges. Daemons are background processes runningunder the operating systems of the communication bridges fulfillingrequests by communication mechanisms by forwarding them to thecommunication stacks. Daemons process data packets received from thenetwork adapters and translate them for the communication mechanisms.

In one embodiment, communication between the communication client and/orthe communication bridges may be performed via a communicationmechanism. The communication mechanism is ensuring communication betweenlogical partitions or virtual machines in a data processing system.

In one embodiment, the communication mechanism may be implemented as asocket network. Sockets as a bidirectional software interface forinter-process or network communication may serve as an embodiment for anetwork with high reliability, and therefore, be used in one or moreaspects.

Alternatively, the communication mechanism could be implemented as aremote direct memory access network (RDMA). This communication mechanismtoo is widely used for network communication and is suited for beingused by one or more aspects.

In one embodiment, the system state information may comprise heartbeatinformation. A heartbeat, being defined as a periodic signal generatedby hardware or software to indicate normal operation or to synchronizeother parts of the data processing system, may be used by one or moreaspects. Usually, a heartbeat is sent between communication bridges at aregular interval of the order of milliseconds. If a heartbeat isn'treceived for a time—usually a few heartbeat intervals—the communicationbridge that should have sent the heartbeat is assumed to have failed.

Due to one embodiment, the own communication stack of a communicationbridge may be a TCP stack. More specifically, a communication stackimplemented in the data processing system where one or more aspects isused, may comprise a TCP/IP stack, too. The TCP/IP stack is outside ofthe operating system of the communication client, and thus, only onedriver (e.g. hardware device driver) has to be developed which may beused by a number of different operating systems, from where acommunication client is accessing this TCP/IP stack outside of its ownoperating system. This may be a very cost effective manner to operate anetwork interface.

In one embodiment, the first operating system and/or the secondoperating system and/or the third operating system is a Linux operatingsystem. Linux operating systems are commonly used open source operatingsystems, exhibiting a very cost efficient possibility to be implementedon a variety of communication bridges.

According to one embodiment, the system state information may containinformation about a data packet count sent and/or received by the mastercommunication bridge. Thus, after a failure of the master communicationbridge and a possible change of the master communication bridge to oneof the other former slave communication bridges, the necessaryinformation will be available to continue the communication traffic. Bythis technique, there will not be any loss of data packets sent orreceived by the communication client.

The system state information may contain information about an identifierfor the last data packet sent and/or received. This feature exhibits avery efficient way of ensuring that no data packet will be lost after afailure of the master communication bridge and a continuation of thecommunication traffic by a new master communication bridge.

According to a further aspect of the invention, a data processingprogram for execution in a data processing system is proposed comprisingan implementation of an instruction set for performing a method asdescribed above when the data processing program is run on a computer.

Further, a computer program product is provided comprising a computerusable medium including a computer readable program, wherein thecomputer readable program when executed on a computer causes thecomputer to perform a method for integrating a further communicationbridge, being a new or recovered communication bridge into a runningdata processing system, the data processing system comprising acommunication client running a first operating system having no owncommunication stack and at least a first communication bridge running asecond operating system having an own communication stack, wherein thefirst communication bridge being configured to act as a mastercommunication bridge and wherein the further communication bridge isrunning a third operating system having an own communication stack. Themethod includes starting the further communication bridge; the furthercommunication bridge requesting from a network adapter and an API of thecommunication client to receive data packets; the further communicationbridge buffering the data packets. Then the method further includes thefurther communication bridge announcing itself as a slave communicationbridge to the master communication bridge at an announcement time; themaster communication bridge monitoring the data packets in a queue ofits communication stack; the master communication bridge executing aquiesce process on the network adapter and on the API of thecommunication client when there are no data packets in the queue with asending time earlier than the announcement time. Further, the methodincludes the master communication bridge extracting the state of itscommunication stack and sending it to the further communication bridge;the further communication bridge setting the received state in its owncommunication stack and informing the master communication bridge aboutcompletion; and the master communication bridge resuming the networkadapter and the API.

As will be appreciated by one skilled in the art, aspects of the presentinvention may be embodied as a system, method or computer programproduct. Accordingly, aspects of the present invention may take the formof an entirely hardware embodiment, an entirely software embodiment(including firmware, resident software, micro-code, etc.) or anembodiment combining software and hardware aspects that may allgenerally be referred to herein as a “circuit,” “module” or “system.”

Furthermore, aspects of the present invention may take the form of acomputer program product embodied in one or more computer readablemedium(s) having computer readable program code embodied thereon.

Any combination of one or more computer readable medium(s) may beutilized. The computer readable medium may be a computer readable signalmedium or a computer readable storage medium. A computer readablestorage medium may be, for example, but not limited to, an electronic,magnetic, optical, electromagnetic, infrared, or semiconductor system,apparatus, or device, or any suitable combination of the foregoing. Morespecific examples (a non-exhaustive list) of the computer readablestorage medium would include the following: an electrical connectionhaving one or more wires, a portable computer diskette, a hard disk, arandom access memory (RAM), a read-only memory (ROM), an erasableprogrammable read-only memory (EPROM or Flash memory), an optical fiber,a portable compact disc read-only memory (CD-ROM), an optical storagedevice, a magnetic storage device, or any suitable combination of theforegoing. In the context of this document, a computer readable storagemedium may be any tangible medium that can contain, or store a programfor use by or in connection with an instruction execution system,apparatus, or device. A computer readable signal medium may include apropagated data signal with computer readable program code embodiedtherein, for example, in baseband or as part of a carrier wave. Such apropagated signal may take any of a variety of forms, including, but notlimited to, electro-magnetic, optical, or any suitable combinationthereof. A computer readable signal medium may be any computer readablemedium that is not a computer readable storage medium and that cancommunicate, propagate, or transport a program for use by or inconnection with an instruction execution system, apparatus, or device.

Program code embodied on a computer readable medium may be transmittedusing any appropriate medium, including but not limited to wireless,wire connection, optical fiber cable, RF, etc., or any suitablecombination of the foregoing.

Computer program code for carrying out operations for aspects of thepresent invention may be written in any combination of one or moreprogramming languages, including an object oriented programming languagesuch as Java, Smalltalk, C++ or the like and conventional proceduralprogramming languages, such as the “C” programming language or similarprogramming languages. The program code may execute entirely on theuser's computer, partly on the user's computer, as a stand-alonesoftware package, partly on the user's computer and partly on a remotecomputer or entirely on the remote computer or server. In the latterscenario, the remote computer may be connected to the user's computerthrough any type of network, including a local area network (LAN) or awide area network (WAN), or the connection may be made to an externalcomputer (for example, through the Internet using an Internet ServiceProvider).

Aspects of the present invention are described herein with reference toblock diagrams of methods, apparatus (systems) and computer programproducts according to embodiments of the invention. It will beunderstood that each block of the flowchart illustrations and/or blockdiagrams, and combinations of blocks in the block diagrams, can beimplemented by computer program instructions. These computer programinstructions may be provided to a processor of a general purposecomputer, special purpose computer, or other programmable dataprocessing apparatus to produce a machine, such that the instructions,which execute via the processor of the computer or other programmabledata processing apparatus, create means for implementing thefunctions/acts specified in the flowchart and/or block diagram block orblocks.

These computer program instructions may also be stored in a computerreadable medium that can direct a computer, other programmable dataprocessing apparatus, or other devices to function in a particularmanner, such that the instructions stored in the computer readablemedium produce an article of manufacture including instructions whichimplement the function/act specified in the block diagram block orblocks.

The computer program instructions may also be loaded onto a computer,other programmable data processing apparatus, or other devices to causea series of operational steps to be performed on the computer, otherprogrammable apparatus or other devices to produce a computerimplemented process such that the instructions which execute on thecomputer or other programmable apparatus provide processes forimplementing the functions/acts specified in the block diagram block orblocks.

Due to a further aspect of the invention, a data processing system forexecution of a data processing program is provided, comprising softwarecode portions for performing a method described herein.

The block diagrams in the figures illustrate the architecture,functionality, and operation of possible implementations of systems,methods and computer program products according to various embodimentsof the present invention. In this regard, each block in the blockdiagrams may represent a module, segment, or portion of code, whichcomprises one or more executable instructions for implementing thespecified logical functions. It should also be noted that, in somealternative implementations, the functions noted in the block may occurout of the order noted in the figures. For example, two blocks shown insuccession may, in fact, be executed substantially concurrently, or theblocks may sometimes be executed in the reverse order, depending uponthe functionality involved. It will also be noted that each block of theblock diagrams, and combinations of blocks in the block diagrams, can beimplemented by special purpose hardware-based systems that perform thespecified functions or acts, or combinations of special purpose hardwareand computer instructions.

What is claimed is:
 1. A method of integrating a further communicationbridge into a running data processing system, the method comprising:obtaining, by a master communication bridge of the data processingsystem, an announcement made at an announcement time by the furthercommunication bridge of the data processing system announcing that thefurther communication bridge is a slave communication bridge, thefurther communication bridge being a new or a recovered communicationbridge, and wherein the data processing system includes a communicationclient running a first operating system having no own communicationstack, and a first communication bridge running a second operatingsystem having an own communication stack, wherein the firstcommunication bridge is configured to act as the master communicationbridge and wherein the further communication bridge is running a thirdoperating system having an own communication stack, wherein master andslave are designations that are switched from one communication bridgeto another communication bridge based on an event, wherein the firstcommunication bridge and the further communication bridge communicate byexchanging system state information on a regular basis; monitoring, bythe master communication bridge, data packets in a queue of itscommunication stack, wherein the master communication bridge, prior toforwarding data packets in the queue of its communication stack to thecommunication client, adds a header to the data packets, wherein theheader includes an internal incoming packet counter for one or moreconnections of the master communication bridge; executing, by the mastercommunication bridge, a quiesce process to quiesce processing on anetwork adapter and on an application programming interface (API) of thecommunication client based on there being no data packets in the queuewith a sending time earlier than the announcement time; extracting, bythe master communication bridge, state of its communication stack andsending it to the further communication bridge; obtaining, by the mastercommunication bridge, an indication of completion by the furthercommunication bridge of setting the received state in its owncommunication stack; and resuming, by the master communication bridge,the network adapter and the API, wherein the master communication bridgeand the further communication bridge are in synchronization.
 2. Themethod according to claim 1, wherein the system state informationcomprises at least one of information about a status of outgoing data orincoming data, or heartbeat information.
 3. The method according toclaim 1, wherein at least one of the communication client, the firstcommunication bridge, or the further communication bridge is implementedas a virtual machine in the data processing system.
 4. The methodaccording to claim 1, wherein communication between the communicationclient and at least the master communication bridge is performed by oneor more daemons running on at least the master communication bridge. 5.The method according to claim 1, wherein communication between thecommunication client and at least the master communication bridge isperformed via a communication mechanism.
 6. The method according toclaim 5, wherein the communication mechanism is implemented as a socketnetwork.
 7. The method according to claim 5, wherein the communicationmechanism is implemented as a remote direct memory access network. 8.The method according to claim 1, wherein the own communication stack isa transmission control protocol stack.
 9. The method according to claim1, wherein the system state information includes at least one ofinformation about a data packet count sent or received by the mastercommunication bridge or information about an identifier for a last datapacket sent or received.
 10. The method according to claim 1, whereinthe event comprises a failure of the one communication bridge or theother communication bridge.
 11. A computer system for integrating afurther communication bridge into a running data processing system, thecomputer system comprising: a memory; and a processor in communicationwith the memory, wherein the computer system is configured to perform amethod, said method comprising: obtaining, by a master communicationbridge of the data processing system, an announcement made at anannouncement time by the further communication bridge of the dataprocessing system announcing that the further communication bridge is aslave communication bridge, the further communication bridge being a newor a recovered communication bridge, and wherein the data processingsystem includes a communication client running a first operating systemhaving no own communication stack, and a first communication bridgerunning a second operating system having an own communication stack,wherein the first communication bridge is configured to act as themaster communication bridge and wherein the further communication bridgeis running a third operating system having an own communication stack,wherein master and slave are designations that are switched from onecommunication bridge to another communication bridge based on an event,wherein the first communication bridge and the further communicationbridge communicate by exchanging system state information on a regularbasis; monitoring, by the master communication bridge, data packets in aqueue of its communication stack, wherein the master communicationbridge, prior to forwarding data packets in the queue of itscommunication stack to the communication client, adds a header to thedata packets, wherein the header includes an internal incoming packetcounter for one or more connections of the master communication bridge;executing, by the master communication bridge, a quiesce process toquiesce processing on a network adapter and on an applicationprogramming interface (API) of the communication client based on therebeing no data packets in the queue with a sending time earlier than theannouncement time; extracting, by the master communication bridge, stateof its communication stack and sending it to the further communicationbridge; obtaining, by the master communication bridge, an indication ofcompletion by the further communication bridge of setting the receivedstate in its own communication stack; and resuming, by the mastercommunication bridge, the network adapter and the API, wherein themaster communication bridge and the further communication bridge are insynchronization.
 12. The computer system according to claim 11, whereinat least one of the communication client, the first communicationbridge, or the further communication bridge is implemented as a virtualmachine in the data processing system.
 13. The computer system accordingto claim 11, wherein communication between the communication client andat least the master communication bridge is performed by one or moredaemons running on at least the master communication bridge.
 14. Thecomputer system according to claim 11, wherein communication between thecommunication client and at least the master communication bridge isperformed via a communication mechanism.
 15. The computer systemaccording to claim 11, wherein the system state information comprises atleast one of information about a status of outgoing data or incomingdata, or heartbeat information.
 16. A computer program product forintegrating a further communication bridge into a running dataprocessing system, the computer program product comprising: at least onecomputer readable storage device readable by at least one processingcircuit and storing instructions for performing a method comprising:obtaining, by a master communication bridge of the data processingsystem, an announcement made at an announcement time by the furthercommunication bridge of the data processing system announcing that thefurther communication bridge is a slave communication bridge, thefurther communication bridge being a new or a recovered communicationbridge, and wherein the data processing system includes a communicationclient running a first operating system having no own communicationstack, and a first communication bridge running a second operatingsystem having an own communication stack, wherein the firstcommunication bridge is configured to act as the master communicationbridge and wherein the further communication bridge is running a thirdoperating system having an own communication stack, wherein master andslave are designations that are switched from one communication bridgeto another communication bridge based on an event, wherein the firstcommunication bridge and the further communication bridge communicate byexchanging system state information on a regular basis; monitoring, bythe master communication bridge, data packets in a queue of itscommunication stack, wherein the master communication bridge, prior toforwarding data packets in the queue of its communication stack to thecommunication client, adds a header to the data packets, wherein theheader includes an internal incoming packet counter for one or moreconnections of the master communication bridge; executing, by the mastercommunication bridge, a quiesce process to quiesce processing on anetwork adapter and on an application programming interface (API) of thecommunication client based on there being no data packets in the queuewith a sending time earlier than the announcement time; extracting, bythe master communication bridge, state of its communication stack andsending it to the further communication bridge; obtaining, by the mastercommunication bridge, an indication of completion by the furthercommunication bridge of setting the received state in its owncommunication stack; and resuming, by the master communication bridge,the network adapter and the API, wherein the master communication bridgeand the further communication bridge are in synchronization.
 17. Thecomputer program product according to claim 16, wherein at least one ofthe communication client, the first communication bridge, or the furthercommunication bridge is implemented as a virtual machine in the dataprocessing system.
 18. The computer program product according to claim16, wherein communication between the communication client and at leastthe master communication bridge is performed by one or more daemonsrunning on at least the master communication bridge.
 19. The computerprogram product according to claim 16, wherein communication between thecommunication client and at least the master communication bridge isperformed via a communication mechanism.
 20. The computer programproduct according to claim 16, wherein the system state informationcomprises at least one of information about a status of outgoing data orincoming data, or heartbeat information.